Refrigeration



March 30, 1943. A. D. SIEDLE REFRIGERATION Filed April 6, 1940 3 Sheets-Sheet 1 INVENTOR Arnold D. qS'l'edle ATTORNEY March 30, 1943. A. D.SIEDLE REFRIGERATION Filed April 6. 1940 5 Sheets-Sheet 2 Arnold 0.Siedle ATTORNEY Patented Mar. 36, 1943 REFRIGERATION V Arnold D. Siedle,Canton, Ohio, assignor to The Hoover'Company, North Canton, OhioApplication April 6, 1940, Serial No. 328,196

' 27 Claims. (01. 62-1195)- This application relates to the art of.absorpf. tion refrigerating apparatus and more particu-' lariy to a,novel construction of such apparatus which provides refrigeration at aplurality of temperature levels.

Heretofore attempts have been made to pro vide absorption refrigeratingmachines which will produce refrigeration simultaneously at a pluralityof temperature levels. These machines meet the technical difficulty thatthe necessary high temperature evaporating level, which preferablyshould be above the freezing point of water to eliminatethe, frostproblem, necessitate the .use of prohibitively large evaporatingelements and even then tend to collect frost at certain localized areasthereof and do not provide desirable .distribution of the refrigeratingeifect. Another dimculty with prior systems is due to the fact that verylow temperature refrigeration is difllcult to achieve in the low temvidean absorption refrigerating machine in which refrigeration is producedat different temperature levels by evaporation of refrigerating mediumwhich is fractionally condensed from the vapors produced in thegenerator.

Itis another object of the invention to utilize v the condensateproduced by rectification of vapors produced in the boiler as arefrigerating fluid before returning such condensate to the boiler.

It is a further object of the invention to reject a portion of the heatof the vapors produced by the boiler of an absorption refrigeratingsystem at a high temperature level and to reject the balance of the heatof such vapors at a low temperature level.

perature refrigerating element because of the presence of small amountsof absorbing solution which find their way into the evaporator.Necessarily prior systems are limited to a rather narrow range ofrefrigerating temperatures due to the inherent limitations involved inthe use of a single refrigerant within the system.

It is a principal object of the invention to provide a multi-temperaturethree fluid absorption refrigerating system which avoids the abovementioned diiiiculties and possesses numerous other advantages peculiarunto itself.

It is a principal object of the present invention to provide anabsorption refrigerating apparatus in which refrigeration may beproduced at a plurality of separated temperature levels within a singlesystem.

It is a further object of the present invention ant produced in acondenser into a pressure equalizing medium and in which highertemperature refrigeration is produced by evaporation into a. pressureequalizing medium from a solution of the absorbent medium andrefrigerant medium which solution is condensed in a separate condenseror rectifying element.

It is an object of the present invention to pro- It is another object ofthe invention to produce a plurality of cooling mediums within a singleabsorption refrigerating system by fractional condensation of vaporsexpelled by the application of heat to a solution of a refrigerant andan absorbent.

It is a still further object of the present invention to provide acompact and economical arrangement of a multi-temperature refrigeratingmechanism in a cabinet construction to the end that a minimum of spaceis utilized by the refrigerating mechanism and to the further end thatthe rejection of heat from various heat re- Jecting elements of theapparatus is allowed to proceed in a highly efficient fashion.

Other objects and advantages of the invention will become apparent asthe description proceeds when taken in connection with accompanying,drawings, in which Figure 1 is an elevational sectional view of arefrigerating mechanism embodying the present invention.

Figure 2 is a partial section and partial dia- 4f grammatic perspectiveview of a modified form ating system which comprises an insulatedcabinet ll having an upper low temperature com-- partment l2 which isseparated from a lower high temperature refrigerating compartment l3 bymeans of an insulated partition I which is, or

may be, made integrally with the cabinet wall..

The compartments l2 and I3 are provided with suitable insulated pivotedclosures or doors l5 and i6, respectively. The cabinet construction alsocompartment ii. A solution reservoir 8 is positioned just above theliquid heat exchanger L and an inclined tubular air-cooled absorber Aextends forwardly and downwardly of the compartment l8 from a positionbeneath the flue IS. A circulating centrifugal fan F which is driven bya sup rposed electric motor M, is mounted in the corner of thecompartment l9 lustabove the absorber A. A slightly inclined tubularair-cooled rectifier R, or primary condenser, extends transversely ofthe compartment is at an intermediate level therein and a tubularair-cooled condenser C is mounted in the upper portion of the chamberIS. A low temperature evaporator E is mounted in the compartment l2 anda high temperature evaporator E i mounted in the compartment II. A gasheat exchanger G is in.- serted in the rear insulated wall of thecompartments l2 and I3 and extends vertically therein. The evaporators Eand E are inserted into the compartments l2 and I3, respectively,through openings 2' and 21, respectively, which are shaped to receivethe evaporators E and E. The openings 28 and 21 are closed by suitableinsulated closure panels 28 and 28, respectively, and each is sealed bya suitable gasket 30.

I The elements of the above described refrigerating apparatus aresuitably connected by various conduits to form a plurality of gas andliquid circuits which constitute a complete refrigerating mechanism.

- The refrigerating mechanism will be charged with a suitablerefrigerant such as ammonia, a suitable absorbent therefor such as waterand a erant in the absorbent. In the case of ammonia and water, forexample, the rectifier R maybe designed to produce a condensat which iscomposed of approximately 20 percent absorbent and 80 percentrefrigerant. Due to the fact that the element R condenses an appreciablequantity of the ammonia vapor, the vapors discharged therefrom to thecondenser through the conduit 33 are substantially pure anhydrousammonia and have had their temperature lowered to a point approachingthecondensing temperature. Therefore a part of the condensing load iscarried, by the element R which rejects an appreciable quantity of heatat a high temperature level and may be made relatively small in size ascompared with the quantity of heat which it is called upon to dissipate.

The substantially pure anhydrous ammonia or refrigerant vapor which issupplied to the upper; end of the condenser C, is liquefied therein byheat exchange relationship with the cooling air flowing through the flueII. The resulting liquid ammonia is conveyed from the condenser C to thebottom portion of the evaporator E by means 'of a conduit 85 whichincludes-1. downwardly extending U-sha'ped portion adapted to form apressure balancing liquid column. The conduit l5 Joins the evaporator Eadjacent its point of suitable pressure equalizing medium, preferably adense inert kas like nitrogen.

A suitable gas burner or similar source of heat H, is mounted in thecompartment I! in a position to heat the boiler B. The gas burner H andthe electric motor M are controlled in a manner to be describedhereinafter.

The application of heat to the boiler 13 gencrates re rigerant vapor andsome vapor of the absorbin solution from the rich solution normallytherein contained. The vapor so produced passes upwardly through theanalyzer D in counterflow lationship with absorbing solution flowing dowardly therethrough and which is supplied from a source to be describedhereinafter. In the analyzer, further refrigerant vapor is added to thevapor supplied from the boiler and some of the absorption solution vaporis removed from such vapor.

After passing through the analyzer D, the partially purified vapors areconveyed therefrom to the lower end of the slightly inclined tubularaircooled rectifier R by means of a conduit 32. In this construction,the element R performs the usual function of a, rectifier but it alsoabstracts sufliclent heat to condense a part of the ammonia vaporsupplied thereto by the conduit 32. Consequently, the condensate formedin the rectlfler R is a very strong solution of the refrigconnectionwith the gas supply conduit 36.

Lean inert gas which is produced in the absorber is conveyed fromtheupper portion thereof into the suction side of the circulating pump F bymeans of the conduit 38 and after being placed under a slight pressureby the fan, it is conveyed therefrom to the bottom portion of theevaporator E by way of conduit 3!, the outer pass of the gas heatexchanger G and the aforementioned conduit Ii.

It is apparent that the pressure prevailing in the conduit 36 willapproach that prevailing in the discharge conduit 39 of the fan. It isdisadvantageous to permit this pressure to be reflected back through thecondenser to the boiler and for this reason the condenser side of the.U-shaped conduit 35 is vented to the rich gas side of the gas .heatexchanger G by means of a conduit 40. The pressure differential betweenconduits 40 and 36 is balanced by a liquid column in the conduit 35.

The evaporator E comprises a pair of vertically spaced substantiallyhorizontal pipe coils 4| and 42 which are serially connected by asuitable riser conduit 43. The form of the evaporator E is preferablysubstantially identical with that disclosed in connection with themodification illustrated in Figure 2 to be described hereinafter.Evaporator E is provided with an anti-blocking drain 5 which isconnected between the upper portionof the bottom coil 4| and the richgas side of the gas heat exchanger G.-

The conduits forming the evaporator E have arelatively smallcross-sectional area whereby the inert gas stream flows therethroughwith a velocity sufllcient to propel the liquid refrigerant therethroughby the frictional drag exerted on the liquid by the inert gas stream.Consequently the liquid refrigerant supplied by the conduit 35 iscirculated through all portions of the evaporator E by the inert gas asthe liquid is evaporating into the inert gas.

The evaporator E is supplied with substantially pure anhydrous liquidammonia and with very,.. lean inert gas. Therefore it operates ata'teiiiperature materially below the freezing point bi water.

changer-VG, the resultinginert gas is discharged into the bottom portionof the evaporator coil EU The evaporator coil E, as illustrated, isposiwhereby the inert gas will flow therethrough at a relatively. lowvelocity. -The vertically extending coil 50 is preferably bonded to avertically extended air cooling plate ii in order to provide a largeheat transfer area The condensate formed in primary/condenser element Ris conveyed from I tioned ina substantially vertical position and is therectifier and v the lowerend thereof into the upper .endof the coll-iiiby =means of a U-shaped. liduldsealing conduit 52 which passes into therear'wall .ofthe cabinet construction. The coil 50 lslprovided.

with a slight continuous downward slope where-I by the ammoniumhydroxide 'wmen .isiusupplled thereto from the rectifier It may nodownward ly by gravity in counterflow relationship to the inert gasstream which flows upwardly through,

the coil 50..

In the evaporator E the refrigerant is rich ammonium hydroxide solution'and its boil.,.-

ing point at the partial "pressure prevailing in the coil; iii isappreciably above the bollin'g'point of the anhydrous ammonia whichissupplied to the evaporator EL Consequently, evaporation which occursinto the inert gas stream flowing through the coil 50 from the ammoniumhydroxide supplied .thereto occurs at a temperature which is above thefreezing point. of ice in order to prevent formation of frost on thecoil 50 and plate 5i but which is sufficiently low in view of of theboileranalyzer system which is vented through the conduit 40 to the richgas side of the as heat exchanger G.

The lean solution is conveyed from the reservoir 8 to the suctionconduit '3! of the fan which opens directly into. the upper end ofabsorber A by means ofthe conduit 5B which includes a finned portionv I!in order to precool the solution and discharges into a gas lift pumpconduit Bl which opens directly into the conduit 38. Pumping gas isconveyed, by a conduit 6i from the discharge conduit 3! of the fan intothe gas lift pump conduit 80 at a point below the liquid level normallyprevailing therein. Consequently, the lean solutlon is elevated into theupper end of the absorber by gas lift action.

The lean solution flows downwardly through the absorber by gravity incounterflow relationship with the inert gas refrigerant vapor mixtureflowing upwardly therethrough and becomes enricher! in the mannerheretofore described.

it thus completing the absorption solution cir-' cult.

the heat transfer area provided by the plate ii ,5

to maintain .safe refrigerating temperatures within the compartment [3.The rectifier is preferably so designed that it will form a solution of.the refrigerant in the absorberof such strength that safe refrigerating.temperatures will be maintained in the compartment l3 without formingfrost on the cooling elements therein. As has been indicated above. asolution containing approximately 20 percent absorbent and 80 percentrefrigerant is one example of. the solution suitable for this purpose. i

After traversing the coil the enriched inert gas is conveyed from theupper end thereof to the bottom portion of the absorber A by means ofthe conduit 54. The rich inert gas then flow upwardly through theabsorber A in counterflow to lean solution flowing downwardlytherethroug h with the result that the solution is enriched byabsorption of the refrigerant vapor content of the inert gas and theresulting heat of absorption is rejected to cooling air flowing over theexterior walls of the absorber conduit and the cooling fins attachedthereto. The resulting lean inert gas is then conveyed by the conduit 38into the fan in the manner described heretofore.

The lean solution formed in the boiler B by the generation ofrefrigerant vapor therefrom is conveyed from the boiler to the solutionreservoir S by way of conduit 55, the liquid heat exchanger L Thematerial supplied to the evaporator E will not evaporate totally andthere will be a material residue which will flow from the lower end ofthe coil 50 into the bottom portion ofthe gas heat exchanger G fromwhich it is drained into the rich gas returnconduit 54 by means of theconduit 08. The conduit 68 includes a U-shaped portion to form a shortpressure balancing column "to balance the'pressure differential whichexists between the bottom portion of gas heat exchanger I G'and theconduit 54. This pressure differential is brought about by the drop inpressure which occurs in the inertgas as it flows through the coil 50.This residue solution then flows through the conduit N and into thestrong solution and into the conduit 83 where it mingles with the strongsolution discharged from the absorber and then returns to the boilersystem in the manner heretofore described.

For purposes of illustration, the boiler 13 herein has been shown asbeing heated by a suitable gas burner H to which gas is supplied bymeans of a suitable conduit It which includes a solenoid controlvalvell. A suitable by-pass I2 is provided around the valve II in orderto supply fuel for a small igniting pilot flame which will be maintainedon the burner H when the valve H is in closed position. The burner H.also includes a suitable flame failure safety cut-off device 13 of aknown type.

Electricalenergy for operating the electrical motor M and the solenoidvalve H is provided by means of a pair of electrical conductors 14 'H.The conductor I8 is also connected to the electrical motor M by means ofan electrical conductor I9. A second thermostatic switch 80 is bridgedacross the conductors I5 and I8 in parallel relationship with thethermostatic switch 'll by means of'a pair of electrical conductorsrespond directly to the temperature of the evaporator. The switch 80will be placed within the compartment I 3 preferably in a position torespond to the temperature of the air circulating therethrough. Theswitches II and 80 have been illustrated diagrammatically herein but itis to be understood that known types of variable refrigerant controlsmay be substituted for each of these thermostatic switches within thescope of the present invention.

It is apparent from the electrical circuitthat completion of the circuitby either of the switches 11 and 80 will simultaneously energize themotor M of the circulating fan F and will energize the solenoid valve'II to raise the same to open position whereby a full flame will becarried upon the burner H and sufficient heat will be applied to theboiler B to generate refrigerant vapor and vapor of the absorptionsolution therefrom.

Preferably each of the coils I and 42 is provided with an overlying flatmetal plateiii which forms a support for stutablexeceptacles such as icetray 86. The space within the compartment I2 beneathhthe coil may.beutilized for refrigerating foodstuffs and a suitable tray 0'I may beprovided for this purpose.

It is preferred to mount an elongated narrow condensate collecting pan88' in the lower portion of the compartment I 3 directly beneath theplate 5| to collect moisture dripping. In the normal operation of theapparatus there will be some collection of moisture on theplate SI andcoil 50 which will not freeze into frost because these elements willoperate at a temperature above the melting point of ice. A high relativehumidity will be maintained in the compartment I3 because of therelativehr high temperature of the refrigerating elements. Theseconditions are particularly desirable in order to provide desirablerefrigeration of foodstuffs without drying the same by moisturecollecting in the form of frost in a low temperature evaporator. Thehigh humidity which will be maintained in the compartment I3 willinhibit serious loss of moisture from foodstuffs stored therein.

The bottom portion of the compartment I! which is formed by the baseelement and particularly that portion of the compartment I8 directlyunder. the chamber I0 will be provided with suitable openings or will beleft substantially entirely open to allow free flow of cooling air intothe compartments I8 and I9. Cooling air will flow first over thesolution precooler 58, then over the air-cooled absorber A, then overthe.

rectifier and primary condenser R, and ultimately over the condenser Cafter which it will exhaust through the top portion of the compartmentsor ducts 19.

The present invention provides a refrigerating mechanism in whichseparate refrigerating elements are placed in distinct'refrigeratingchambers and are supplied with refrigerants having differentcharacteristics but all coming from 8 gen and higher temperaturerefrigeration-will.

be produced by evaporation from a solution of ammonia in-water, ammoniumhydroxide, into the inert gas; and-both the anhydrous ammonia and theammonium hydroxide will be supplied from a sing'lerefrigerating system.

Due to the parallel connection-of the control switches TI and 80, therefrigerating mechanism" will be energized to produce refrigerationwhenever there is demand for refrigeraiton in either of A thecompartments It or I3 and such production of refrigeration will continueuntil such time as the refrigerating demands of both compartmentshavebeen satisfied. This insures that no part of the apparatus whateverwill be without ability to meet its refrigerating load.

Referring now to Figure 2, there isillustrateda modified form of theinventions This 'form of the invention is identicalwith that disclosedin Figure 1 except for the arrangement of the high temperaturerefrigerating element. Conseq'uent ly, the refrigerating mechanismsrelationship to the cabinet structure has not been shown except therelationshipof the evaporating elements to the refrigeratingcompartment.- -It will be under-- stood that this arrangement isidentical with that disclosed in Figure 1. In order to eliminateneedless duplications of description, those portions of the mechanism ofFigure 2 which are identical with portions of the apparatus previous lydescribed in connection with Figure 1 are given the same referencecharactersprimed except that the low temperature-evaporator is given asubscript I. v

In this form of the invention the high temperature refrigeratingcompartment I3 is refrigerated by a' horizontal coil I00whi'ch lies inthe upper portion thereof or just below the mad-- lating dividing panelII. A sheet metal heat transfer plate MI is mounted in heat exchangerelationship with the under side of the coil I00 in order to provide alarge heat transfer area.

The inert gas flows from the circulating fan F through the evaporator E1and discharges through the conduit 46' into the inner pass of the gasheat exchanger exactly in the manner heretofore described in connectionwith the cor responding elements of Figure 1. The partially enriched gasthen .flows through the inner pass of the gas heat exchanger G and isconveyed from the bottom end thereof into one end of the horizontal coilI00 by means of conduit I03. The inner pass of the gas heat exchanger Gis drained to the strong solution return conduit 63' by a drain conduitI01.

The evaporator coil I00 is made of a small diameter conduit whereby theinert gas flows therethrough with a velocity su'fficient to propel ordistribute the liquid refrigerant therethrough by the frictional drag ofthe inert gas stream. The condensate formed in the rectifier Ris'conveyed from the lower end thereof into the coil I00 adjacent itsjunction with the conduit I03 by means of a downwardly extended U-shapedcon-' duit I05 which will provide a pressure balancing column tomaintain the pressure differential which normally exists between theconduit I03 and rectifier R.

The condensate which is discharged into the coil I00 is propelledtherethrough by the inert the gas which is evaporating and producesrefrigeration at a temperature which is low enough to maintain saferefrigerating conditions in the compartment it but which is high enoughto maintain a relatively high-humidity condition in the compartment 13'.

The rich gas and unevaporated liquid which completely traverses the coilI -is .conveyed therefrom to the bottom portion of the absorber A bymeans of conduit I06. The gas then flows upwardly through the absorberin-the manner described in Figure 1 and the liquid flows through theconduit 63' and ultimately returns through the conduit 64' to the upperportion of the analyzer D..

This form of the invention operates identically with that .describedheretofore in connection with Figure 1 and will be provided with anidentical control and heating system.

In this form of the invention, however, the high temperature evaporatoris horizontally positioned in the upper portion of the high temperaturecompartment 13' whereby it consumes a minimum of. space therein and therefrigerating liquid supplied to the coil I00 flows therethrough inparallel flow relationship with and under the propelling force of theinert gas as distinguished from the arrangement disclosed in Figure 1 inwhich the liquid refriger'antin the-coil 60 flows by gravity incounterilow relationship to the inert gas. Also in this form of theinvention, the openings and inserts therefore in the rear wall of thecabinet will naturally extend transversely thereof on a horizontal planeinstead of vertically as is the case in connection with the apparatusdescribed in connection with Figure 1 because. of the horizontalevaporator construction used in the compartment l3.

Referring now to Figure 3 there is disclosed another modified form ofthe invention in which the inert gas is circulated by the densitydifferential existing between'cold rich gas discharged from theevaporator and warm lean gas discharged from an absorber and in whichthe absorbing solution is circulated by means of a heat operated vaporlift. pump.

The cabinet construction preferably utilized in this form of theinvention is identical with that preferably utilized in the form of theinvention discussed above in connection with Figure 1. Therefore, only aportion of the cabinet 'hasbeen shown in order to illustrate itsrelationship to the cooling elements and identical portions of thecabinet in Figures 1 and 3 have been given the same reference charactersexcept those in Figure 3 are double primed.

This form of the invention comprises a boiler 20!, an analyzer 20i, anelongated slightly inclined tubular finned rectifier and primarycondenser 202, a tubular air-cooled condenser 202, 'a low temperatureevaporator 204, a high temperature evaporator 205, a gas heat exchanger206, an inclined tubular air-cooled absorber 201, a solution reservoir208, and a liquid heat exchanger 209. These elements are suitablyconnected by various conduits to form a completerefrigerating system.

The thus described refrigerating system will be charged with a suitablerefrigerant such as ammonia, a suitable absorbent therefore such aswater, and a pressure equalizing medium preferably a light inert gaslike hydrogen.

The control mechanism for this form of the invention may be identicalwith that disclosed in connection with Figure 1 except that there willbe no connection for controlling a circulatingfan.

The application of heat to the boiler 200 produces vapor of refrigerantand absorption solution therein which flows upwardly through the vaporlift pump 2i. and conveys solution upwardly therethrough into theseparation chamber 20L From. the separation chamber. 2, the

vapors are conveyed to thelowerend of therectifier 202, by means of theconduit 2! I After passing through the rectifier 202, the resultinganhydrous ammonia-vapor is conveyedtherefrom tothe upper end of thecondenser 202 by means of conduit 2l2.. The vapor isthen liquefiedin thecondenser, and is discharged therefrom through the conduit 2i! into theupper coil 2 of the evaporator 20!. I

The evaporator coil 2 is given a slight downward inclination in order toprovide for gravity flow of the liquid refrigerant therethrough. .Thecoil 2i 4 is in heat exchange relation with a plate 2il which ispreferably ofv aluminum and has a horizontal upper surface. The distancebetween the horizontal upper surface of the plate 2i! and the coilpositioned therebelow increases from the liquid inlet portion of thecoil to the liquid outlet portion thereof. C0112 is serially connectedto a lower identical coil 2|! by means of a conduit 2ll.- The coil 2i.is likewise in heat exchange relationwlth a heavy plate 2i5.

Lean inert gas-formed inrthe absorber 2" is conveyed therefrom to .oneend of the lower coil 2| of the evaporator'by-way of the conduit Ill,

the outer pass of the gas heat exchanger 200 and the evaporator gassupply conduit 2".

The inert gas flows upwardly through the evaporator 2l4in counteriiowrelationship with the liquid refrigerant flowing downwardlytherethrough. The liquid refrigerant evaporates into the inert gas whichproduces refrigerating effect at a low temperature.

from flowing into the gas heat exchanger. After traversing the gas heatexchanger, the inert gas than flows through the conduit 224 into thebottom portion of an evaporator coil 226 which has attached thereto anextensive air cooling plate 220.

The condensate formed in the rectifier 202 is conveyed .from the lowerend thereof into the upper end of the coil 228 by means of a U-shapedconduit 221. The liquid refrigerant flows downwardly through the coil225 by gravity in counterflow relationship to the inert gas flowingupwardly therethrough. The refrigerant evaporates into the inert gas toproduce a refrigerating effeet at a temperature such that frostdeposition upon the coil 225 and plate 228 will be inhibited and saferefrigerating temperatures will be maintained in the compartment |3'-.

The resulting rich gas'formed in the coil 225 is conveyed from the upperend thereof to the bottom portion of the tubular inclined absorber 201by means of a conduit 230. The rich inert counterflow relationship withthe lean absorption solution flowing downwardly therethrough. Therefrigerant vapor content-of the gas is absorbed in the liquid and theresulting heat of absorption is dissipated to cooling air flowing overthe exterior walls of the absorber conduit and the cooling fins attachedthereto. Resulting lean gas is then discharged from the upper end of theabsorber bymeans of the conduit M8 in the manner 'described above. Y

Circulation of inert gas is achieved in the following manner: A colddense column of gas discharging through the conduit 222 is maintained inthe inner pass of the gas heat exchanger 208. This gas has a greaterweight than the warmer and-lighter lean gas which is flowing upwardlythrough the outer pass of the gas heat exchanger from the absorber...There is also maintained a. cold dense, rich gas column in the conduit230 which has a greater average density than the gas column in theevaporator coil 22!. These factors contribute to produce a circulationof the inert as by gravity.

Although the evaporator for the compartment 13', has been described as avertical pipe'which may be positioned adjacent one side. or the rearwall of the compartment "I3", it is within the scope of the presentinvention to place this coil in a horizontal position inclined slightlyto produce flow in the top part of the compartment ll just beneath thepartitionfl";

The loan solution which is discharged the separation chamber!" =by-th'evapor lift pump- 2|. is conveyedntherefrom to the upper end of theabsorber 281 by gravity through the conduit 2; the liquid heat exchanger2 and conduit l. The absorbing solution flows downwardly through theabsorber 20l'by gravity counter tothe-inert gas flowingupwardlytherethrough and is strengthened by'absorbing refrigportion of the coil22! to the boiler by means of the conduit 2, the conduit 22! and theboiler return conduit '22 I It will be understood that the absorber,rectifler, condenser, and boiler will be arranged in the cabinetsimilarly to the manner in which the corresponding elements are arrangedin the apparatus illustrated in Figure 1.

This form of the invention, like those described heretofore, provideslow temperature refrigeragas then flows upwardly through the absorber inevaporation into the inert gas from a,v solution j of thetref'rigerantin the absorbent.

In accordance wtih" the present invention, a single refrigerating systemis provided with a plurality of evaporators designed to operate atdifferent temperature levels and is so constructed 1 and arranged as tosupply refrigerating liquids having different characteristics toseparate evaporators without the utilization oi'a complexrefrigeratingiiuid.

The illustrated location of the rectifier is most convenientstructurally asit allows the useof short direct connections to theboiler and low temperature evaporator. However; therectifler can bepositioned above or on a level with the condenser thus placing the hightemperature heat reiector at the top ofthe air flue. 1 The disclosedarrangement in which the inert gas traverses-the low temperatureevaporatorbe- I :1. That method-of producing a' reirigerating eflect'.at a plurality of temperature levels which includes the'stepsofexpellingvapor from'a-so lution of refrigerant and an absorbent,liquefy ing such vapors toproduce liquids of different refrigerantconcentration, andevaporating such liquids of diii'erent refrigerantconcentration in separate evaporating zones. 1 l a 2. That improvementin the art of absorptionrefrigeration .which includes thesteps-ofapplying heat to a solution of a refrigerant in an absorbent toexpel vapors therefrom, rectifying such vapors by the extraction of heattherefrom in an amount suiiicient to liquefy substantiallyall vapot ofthe absorbent and to liquei'y a portion of the vapor of the refrigerant,liquefying the'residue vapor to produce refrigerant liquid which issubstantially free of absorbent contacting the refrigerant liquid withan inert gas to produce a refrigerating eifect at a first temperaturelevel, and contacting an inert gas with the liquid produced byrectification to produce refrigeration at a second temperature level.

tion by evaporation from substantially anhydrous refrigerant in a lowtemperature evaporator and provides higher temperature refrigeration byevaporation from a verystrong solution of refrigerant in the absorbentin a high temperature evaporator. All circulation of the refrigerant isby gravity as is the circulation of the inert gas and circulation ofsolution is achieved by a heat operated pump.

Thus, the present invention provides an absorption refrigeratingapparatus in which low temperature refrigeration is achieved byevaporation of liquid refrigerant into the inert gas and in which hightemperature is achieved by 3. That method of producing a refrigeratingeil'ect ate. plurality of temperature levels which includes the steps ofexpelling vapor from a solution of refrigerant and an absorbent,liquefying such vapors to produce liquids of different refrig erantconcentration, and evaporating such liquids of diiierent refrigerantconcentration in separate evaporating zones in contact with a press sureequalizing medium which is inertwith re. spect to the refrigerant andthe absorbent and while the pressure equalizing medium and all liquidsof diflerent refrigerant concentrations are subjected to substantiallythe same total pressure.

4. That improvementin refrigerating systems of the type in whicha'refrigersnt vapor is ex pelled fromsolution in an absorbent by theapplication of'heat, the refrigerant is separated from vapor of theabsorbent by condensation of such absorbent vapor-and a portion of therefrigerant vapor-and the remaining vapor-is sense ratelyv condensed toliquid refrigerant whichincludes the steps of flowing an inert gas incontact with the aforesaid liquid refrigerant to produce a firstrefrigerating efifect thereafter flowing said inert gas into contactwith thesaid condensed absorbent and the refrigerant condensedtherewith; and thereafterpassingsaid inert gas a second liquidwhichco'ntains the residue of the refrlgerantvapor condensed to liquid afirst cooling unit, means for supplying said first liquid thereto forevaporation to produce a -refrigerating effect at a first temperaturelevel, a

9. A'refrigerating apparatus comprising a solution circuit including agenerator and an absorber, an inert gas circuit including "said absorberand first and secondcvapora'tors, a rectifier connected to receivevapors from sald'generator and to'dlscharge condensate into saidfirstfevap orator,- a condenser connected to :receive vapor fromsaid-rectifier and to discharge condensate into said second evaporator,and means'in said inert gas circuit for propelling inert gas through oneof said evaporators with a velocity sufiicient to distribute thecondensate therethrough by the frictional dragof the inert gas. v 1 l10. A refrigerating apparatus comprising a solution circuit including agenerator and an absorber, an inert gas circuit includingsaid absccondcooling unit, and means for conveying" said second liquid into saidsecondflcooling unit for evaporation :to produce a refrigerating:-effect atasecond'temperature level;

6. In an absorption refrigerating mechanism,

1 means for expelling refrigerant vapor and absorbent vapor from asolution'of refrigerant and ab- 3 sorbent fractional condensing meansfor condensing saidvapors and for separately discharging a first liquidwhich contains the condensed absorbent and a portion'of-the condensedrefrig .erant vapor andaisecond-liquid which "contains the residue ofthe refrigerant vapor condensed j. to liquid phase, a first coolingunitand a second cooling unit'connected to be subjected to the sametotal pressures, and means for supplying said first and second liquidstosaid first and second cooling units, respectively, for evaporationtherein whereby refrigeration is produced in said firstv and secondcooling units at different temperature levels while said coolingunitsare ma'intained at the same total pressure.

7.. Inc refrigerating device, a cabinet including a mechanismcompartment arranged to allow a flow of cooling air therethroughand aninsulated compartment-divided into a freezing chamher and a storagechamber, a refrigerating mechanism comprising a freezing unit in saidfreezing chamber, a cooling unit in said storage chamber,' I means insaid mechanism compartment for producing vapor of a refrigerant mixedwith vapor of an absorbent, an air-cooled rectifier positioned to becontacted by cooling'air in said compartment,.means for conveying saidvapors to said rectifier, means for conveying condensate formed in saidrectifier into said cooling unit, an aireooled condenser positioned tobe contacted by cooling air in said compartment connected to receivevapors not condensed in said rectifier and to discharge condensate intosaid freezing unit,

and means for removing vapor-sfrom said freezing and coolin u i 8. Arefrigerating apparatus comprising a solution circuit including agenerator and an absorber, an inert gas circuit including said absorberand first and second evaporators, a rectifier connected to receivevapors -from said generator and-to discharge condensate into said firstevaporator, and a condenser connected to receive vapor from saidrectifier and to discharge condensate into said second evaporator, saidinert gas circuit being so arranged that inert gas flows sorber andfirst and second evaporators, said'fi'rst evaporator comprisinganupstanding conduit, said second evaporator comprising a substantiallyhorizontal conduit; a rectifier connected to re-- ceive vapors fromsaidgenerator and to discharge condensate into the' upp r portion of saifirst evaporator- 1oz gravityfiow therethrough, and a' condenser.connected to receive vapor from said rectifier and. to dischargecondensate into said 1 secondevaporator; Y, a

. ILA refrigerating apparatus comprisinga solution circuit includingageneratori: and 'an air-- sorber. an inert gas circuitincluding'saidabsorber and first and second Ievaporators; said first andsecond evaporators comprising-substantially horizontal conduits,- arectifier connected -to"re+ ceive vapor from said generatorand-to'discharge condensate into said first evaporator; a condenserconnected to receive vapor from said rectifier and to dischargecondensate into said "sec0nd 'evap-' orator, and means in saidinertgascircuit for' propelling inert gas through said evaporators witha. velocity sufilcient to sweep or'drag the condensate therethrough. I

l2. Anabsorption refrigeratingapparatus comprising a first evaporatorhaving a slope sufilcient to cause liquid to fiow therethroughby'gravity, a

second evaporator positioned above said first I evaporator and alsohaving a sicpe'sufiicientto cause liquid to flow ,therethrough bygravity,

means for supplying a refrigerating liquid to the upper portion of eachof said evaporator-s, an ab sorber positioned below said evaporator-s, agas conduit system for conveying lean inert gas from said absorber tosaid second evaporator. a gas conduit system for conveying inert gasfrom said second evaporator downwardly to thelower end of said firstevaporator, and a gas conduit systern for conveying inert gas from theupper end of said first evaporator downwardly to said absorber wherebyilow of inert gas through said second evaporator is produced by thedensity differential between the warm lean 8'88 ascend ing from saidabsorber to said second evaporator and the cold partially enriched gasdescending from said second evaporator to'said first evaporator and fiowof inert gas through said first evaporator is produced by the densitydifferential between the gasfascending through said first evaporator andthe colder richer gas descending from the upper portion of saidfirst-evaporator to said absorber. 1

l3. Refrigerating apparatus comprising a freezing chamber, an evaporatorpositioned within said ri'reezing chamber comprising a substantiallyplane coil inclined slightly from the horizontal to. provide for gravityflow of refrigerant therethrough one of said evaporators counter to thedirection of fiow of condensate therethrough;

- ature refrigerating chamber comprising through. an, coil comprising aplurality of elongated conduit portions serially connected at theirends, means for supplying refrigerant liquid to the upper portion ofsaid coil, means for circulatlng. an inert gas through said coil, and ametallic plate over-lyingandthermally bondedto atileast the major areaof one side of said coil,

said plate having a substantially horizontal upper face to; provide anuntilted support for receptacles and the. like, certain of said conduitportions of i said coil underlying the central portion of said plate. zV I V r 14-. Refrigerating apparatus comprising a refrigeratingcompartment, means separatingsaid compartment into a low tempearturerefrigerating chamber and a high temperature refrigerating chamber, anevaporator in said low tempera substantially plane coil inclinedslightly from the horizontal to provide gravity flow of refrigeranttherethrough, a-metallicheat conducting plate having a horizontaluppersurface to provide a solution from whichlthe-vapor'wasexpeiledpreviously which includes the steps of rejecting heat for supplying;arefrigerant liquid to each of-said 1 coils, 'andameans forcirculatingan inert --gas through each of said: coils *in contact withthe refrigerantliquid supplied thereto. 1 Y

. l5. Ina-a refrigerating apparatus, a -cabinet structure having aninsulated refrigerating charm" ber divided into:superposed high andlowtemperature refrigerating compartmentsfa mechanism compartmentextending below said high and low temperature compartments andvertically along one wall of said chamben an absorption refrigeratingmechanism associated with said cabinet comprising an evaporator in eachof said refrigerating compartments, an air-cooled absorber lying in saidmechanism compartment below said evaporators, means providing an inertgas circuit including said'evaporatpra and said absorber, and means forsupplyingrefrigerant. liquid to the evaporator in said low temperaturerefrigerating compartment and for supplying a mixture of refrigerantliquid and absorption s0- lutionto the evaporator in said hightemperature refrigerating compartment including air-;

cooled condensing means mounted in the vertically extending portion ofsaid mechanism compartment.

16. In a refrigerating apparatus, a cabinet structure having aninsulated refrigerating chamber divided into high and low temperaturerefrigerating compartments and a mechanism compartment structureextending below and along one wall of said refrigerating chamber, anabsorption refrigerating mechanism comprising an evaporator in each ofsaid refrigerating compartments, an absorber in said mechanismcampartment, a generator in said mechanism compartment connected to saidabsorber in an absorbing solution circuit, means connecting saidevaporators and said absorber in an inert gas circuit, condensing meanspositioned in said mechanism compartment adjacent one wall of saidchamber and connected to receive vapors from said generator, saidcondensing means ineluding a first air-cooled portion which rejects heatat a high temperature and supplies condensate including liquidrefrigerant and absorption solution to the evaporator in said hightemperature refrigerating compartment, and a second air-cooled portionconnected to receive va-' pors previously cooled in said first portionwhich rejects heat; at a lower temperature level than said first to; theevaporator in said frigerating compartment.) A 17. That improvement inabsorption refrigerating'systems of the type involvingcexpulsion ofvapors from a solution of a refrigerant in'an absorbent by theapplication of heat; liquefaction of. the vapors byextraction ofrheattherefrom into a cooling air, evaporation of. the liquid-into a gaswhich-is. inert with respect to the refrigerant and the absorbent,andabsorptionof the low temperature revapor produced by evaporation fromthe inert gas by ,contactlngthe inert gas and vapor with at a firsttemperaturelevel from vapors freshly expelled .from solution'to converta portion of such. vapors to 'a-liquid comprising refrigerant andabsorbent, rejecting heat at a second temper-.- avure level from vapornot liquefied at said first temperature level to convert. anotherportion of said vapor to liquid refrigerant; and producing re-'frigerating effects by, evaporating .liquids :produced atsaicl firstandsecondtemperature levels into a movingbody 0 inert. gas-in separatedevap- 101185 1 y- 131,; 11113. g 5 J, 8,, That improvement: in;.absorption refrigersting systems pf heit einvolving expulsion ,of vaporsfrom .ajcolutionlofl, aaref ilgerant in anabsorbent ,bythe applicationofsheat, liquefaction of-theyapors by 'extmqtion of heet therefrom intoacooling air; ,evaporation of -the='liquid:-into a gas which is inertwith respect-to the refrigerant and the absorbent, andaabsorption :ofthe vapor produced by *evaporation from the inert gas by contactingtheinert gas and vapor with solution fronrwhlch the vapor was expelledpreviously which includes the steps of rejecting heat at a firsttemperature. level from vapors freshly expelled from solution, toconvert a portion of uid produced at the other such vapor to .a liquidcomprising refrigerant-and absorbent, rejecting heatat a secondtemperature level from vapor not liquefied ,at said first temperaturelevel to convert another portion of said vapor to liquid refrigerant,producing a first refrigerating effect by contacting the liquid-prmduced at one of said'temrperature levels with a moving body of the inertgas, and producing a second refrigerating effect by contacting the liqofsaid temperature levels with said moving-body of inert gas.

19. In a refrigerating apparatus a cabinet having a refrigeratingportion and a mechanism and heat rejecting compartment arranged for flowof cooling air therethrough, an absorption refrigerating mechanismassociated with said cabinet comprising a plurality of cooling .units inheat portion and supplies refrigerant. liquid refrigerant liquids ofdifferent refriger meri s bein so arranged with respect to saidgenerator that it receives a vapor mixture of refrigerant and absorbentand discharges a liquid consisting of refrigerant and absorbent andsubstantially pure refrigerant vapor, another of said condensingelements being arranged to receive substantially pure refrigerant vaporfrom said one condensing element and to discharge substantially pureliquid refrigerant, and means for conveying condensate from each of saidcondensin elements into an associated evaporator.

21. In a device of the character described a cabinetstructure includingan insulated refrigerated chamber, an absorption refrigerating mechanismassociated with said cabinet structure, said refrigerating mechanismincluding a. freezing evaporator in said refrigerated chamher, an aircooling evaporator in said refrigerated chamber, a generator, arectifier connected to receive vapors from said generator and to supplya mixture of condensed refrigerant and condensed absorbent to said aircooling evaporator, and a condenser connected to receive vapor from saidrectifier and to discharge refrigerant liquid into said freezingevaporator, said rectifier and said condenser being positionedexteriorly of said refrigerated chamber.

22. In a device of the character described, a cabinet structureincluding a refrigeration cham-- ber and a machinery compartment havingan upstanding air fiue, an absorption refrigeration mechanism associatedwith said cabinet structure 1 including a generator, a rectifier, anabsorber and 1 a condenser in said mechanism compartment, 9. i freezingevaporator positioned in the upper portion'of said refrigerated chamber,a space cooling evaporator mounted in said refrigerated chamber belowsaid freezing evaporator, said condenser being of the air cooled typeand positioned in the upper portion of said air duct, said rectifierbein of the air cooled type and positioned in said air duct beneath saidcondenser, means for conveying liquid refrigerant from said condenser tosaid freezing evaporator, means for conveying liquid refrigerant andcondensed absorbent from said rectifier to said space coolingevaporator, means providing for circulation o an inert gas between saidabsorber and said evaporators, means providing for circulation ofabsorbent between said absorber and said generator, means for conductingvapor of refrigerant and absorbent from said generator to saidrectifier, and means for conducting refrigerant vapor from saidrectifier to said condenser.

23. That improvement in the art of refrigeration which includes thesteps of expelling vap r of refrigerant and absorbent from a solution ofrefrigerant and an absorbent, condensing the va por of the absorbent andpart of the refrigerant vapor to produce a first refrigerant liquid,evaporating the first refrigerant liquid to produce a firstrefrigerating effect, condensing the balance of the refrigerant vapor toproduce a second refrigerant ,liquid, and evaporating the secondreiiifrigerant liquid to produce a second refrigerating-- absorbent and aportion of the condensed refrigerant vapor and a second liquid whichcontains the residue'of the refrigerant vapor condensed to liquid phase,a first cooling unit, a second cooling unit, means for conveying saidfirst and second liquidsto said first and second cooling units,respectively, means serially connecting said first and second coolingunits for fiow of an inert gas therethrough, means for supplying aninert gas to one of said units and means for removing inert gas from theother of said units.

25. A refrigeratingapparatus comprising a solution circuit including agenerator and an absorber, an inert gas circuit including an absorberand first and second evaporators, a rectifier connected to receivevapors from said generator and to discharge condensate into said firstevaporator, and a condenser connected to receive vapor from saidrectifier and to discharge condensate into said second evaporator.

26. A refrigerating apparatus comprising a solution circuit including agenerator and an absorber, an inert gas circuit including an absorberand first and second evaporators, said first evaporator comprising anupstanding conduit, said second evaporator comprising a substantiallyhorizontal conduit which is sloped slightly to provide for gravity flowof a liquid therethrough, a rectifier connected to receive vapor fromsaid generator and to discharge condensate into the upper portion ofsaid first evaporator, and a condenser connected to receive vapor fromsaid rectifier and to dischar e condensate into the highest end of saidsecond evaporator, said inert gas circuit being so arranged that inertgas flows through said evaporators in counterflow relationship with thecondensate supplied thereto.

27. An absorption refrigerating apparatus comrising a first evaporator,a second evaporator, a generator, a rectifier connected to receivevapors from said generator and to discharge condensate into said firstevaporator, a condenser connected to receive vapor from said rectifierand to discharge condensate into said second evaporator, an absorberconnected in circuit with said generator for circulation of an absorbingsolution, a gas heat exchanger having one pass connected to receive leaninert gas from said absorber and to discharge such lean inert gas intosaid second evaporator, said gas heat exchanger having a-second passconnected to receive rich inert gas from said second evaporator and todischarge such rich inert gas into said first evaporator.

ARNOLD D. SIEDLE.

